The midgut proteases of the cockroach Leucophaea maderae will be further purified and characterized by their physico-chemical properties. Antibodies will be prepared against the various proteases which will then allow the development of a sensitive radioimmune assay and the localization of the enzymes in the midgut epithelium. The mode of protease induction will be further investigated in detail. Radio- labeling of the proteases suggest de novo synthesis in the midgut epithelium. An in vitro synthesis of proteases by epithelial cultures will also be attempted. The mode of synthesis and secretion of the proteases by membrane-bound polysomes will be investigated. The function of the peritrophic membrane and its properties is of interest in this context, and its permeability characteristics for macromolecules will be determined.